The Physiological Impact of GFLV Virus Infection on Grapevine Water Status: First Observations

Anastazija Jež-Krebelj,Marija Stele,Maruša Pompe-Novak,Paolo Sivilotti,Maja Rupnik-Cigoj,Marko Chersicola

doi:10.3390/plants11020161

Abstract

In a vineyard, grapevines are simultaneously exposed to combinations of several abiotic (drought, extreme temperatures, salinity) and biotic stresses (phytoplasmas, viruses, bacteria). With climate change, the incidences of drought in vine growing regions are increased and the host range of pathogens with increased chances of virulent strain development has expanded. Therefore, we studied the impact of the combination of abiotic (drought) and biotic (Grapevine fanleaf virus (GFLV) infection) stress on physiological and molecular responses on the grapevine of cv. Schioppettino by studying the influence of drought and GFLV infection on plant water status of grapevines, on grapevine xylem vessel occlusion, and on expression patterns of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1), 9-cis-epoxycarotenoid dioxygenase 2 (NCED2), WRKY encoding transcription factor (WRKY54) and RD22-like protein (RD22) genes in grapevines. A complex response of grapevine to the combination of drought and GFLV infection was shown, including priming in the case of grapevine water status, net effect in the case of area of occluded vessels in xylem, and different types of interaction of both stresses in the case of expression of four abscisic acid-related genes. Our results showed that mild (but not severe) water stress can be better sustained by GFLV infection rather than by healthy vines. GFLV proved to improve the resilience of the plants to water stress, which is an important outcome to cope with the challenges of global warming.

Highlights

Grapevines are exposed to several abiotic and biotic stresses, especially as they are propagated in a vegetative way
Schioppettino (Vitis vinifera L.) revealed a complex interaction of Grapevine fanleaf virus (GFLV) infection and drought stresses that led to an impact on the water status of plants
The measurements collected before the water stress start highlighted the impact of GFLV infection alone, significant one day before the start of water stress (Figure 1); both ΨSTEM and root hydraulic conductivity (RHC) were lower in the case of infected well-watered (I WW) vines, and the magnitude of difference was much higher in the case of RHC (Figure 1B)

Summary

Introduction

Grapevines are exposed to several abiotic (drought, extreme temperatures, salinity) and biotic stresses (phytoplasmas, viruses, bacteria), especially as they are propagated in a vegetative way. Both abiotic and biotic stresses are responsible for dramatic economic losses and represent the main limiting factor for viticulture worldwide. One of the most important and widespread virus diseases of grapevine is Grapevine fanleaf degeneration [3,4], which occurs in all grapevine-growing regions throughout the world [5] This disease is caused by Grapevine fanleaf virus (GFLV), which is a member of the genus Nepovirus [6].

Methods

Results

Conclusion